   (remove-pages! [_ state page-ids]))
 
 (defprotocol ColumnDropTarget
-  (accept-drop!  [_ state pages]))
+  (accept-drop!  [_ state pages target-idx]))
 
 (defrecord InboxColumnSource [id]
   ColumnSource

                  (om/value new-pages))
        (om/set-state! owner :selection
                       (selection/make-selection new-pages)))))
  (render-state [_ {:keys [selection handle-drop!]}]
    ;; NOTE: `column' needs to be a value OR we need to extend cursors
    [:.column {:on-drag-over (fn [e]
                               (when (satisfies? ColumnDropTarget (om/value column))

(defn ^:private mark-page-selected
  "Assocs {:selected? true} to `page' if `selected-pages'
  contains (:id page). Used in `index-column'."
  [page selected-pages]
  (assoc page :selected? (contains? (set selected-pages) (:id page))))

(ui/defcomponent inbox-column [[state column] owner opts]
